Some vehicles include an operational mode in which a computing system is used to navigate and/or maneuver the vehicle along a travel route with minimal or no input from a human driver. Such vehicles are equipped with sensors that are configured to detect information about the surrounding environment, including the presence of stationary and dynamic objects in the environment. Sensor data from multiple sensor types can be fused to provide a detailed understanding of the objects in the environment, including the speed of such objects. The computing systems are configured to process the detected information to determine how to navigate and/or maneuver the vehicle through the surrounding environment.